van vlbck



UNITED STATES PATENT OFFICE.

V. VAN VLEGK, OF NEW YORK, N. Y., ASSIGNOR TO HIMSELF AND RALPH LOOKVVOOD, OF

NEWv YORK, N. Y.

DENTAL CHAIR.

Specification of Letters` Patent No. 30,706, dated November 20, 1860.

To all whom it may concern:

`Be it known that I, V. VAN VLEoK, of the city, county, and State of New York, have invented a new and Improved Dental Chair; and I do hereby declare that the following is a full, clear, and exact description of the same, reference being had to the accompanying drawing, forming a part of this specification.

The drawing represents a vertical central section of this invention.

My invention consists in the arrangement of a longitudinally sliding bolt in combination with the seat of a chairv and with two hemispheres one working inside the other in such a manner that by depressing said bolt the seat of the chair may be retained in any desired position, whether horizontal or inclined; also in the combination with said longitudinally sliding bolt and with the two hemispheres of two toggle arms acting on the head of the bolt and acted upon by al treadle in such a manner, that by depressing the treadle the two hemispheres are locked and the seat retained in its position.

To enable those skilled in the art to make and use my invention, I will proceed to describe its construction and operation with reference to the drawing.

The seat A, of the chair is fastened to the upper vsurface of the hemisphere B, which is provided with a flange a, by means of screws Z). The hemisphere B tits into the top end of the foot or stand O, said top end being hollowed out so as to form a socket D, and in the center of the upper surface of the hemisphere B, a socket E, is formed which receives the hemisphere F. A bolt G, which is firmly secured in the hemisphere F, passes through a conical recess c, in the hemisphere B, and through a central opening in the stand down near to the ground, and the recess c, in the hemisphere B, is of such a size and it is so formed, that said hemisphere is at libert-y to move in the socket D, without coming in contact with the bolt G.

By exerting a slight pressure in a downward direction on the bolt G, the two hemispheres are kept down in their respective sockets and the hemisphere B, with the seat can be brought in a horizontal or in an inclined position as may be desired, while the hemisphere F, always retains its horizontal position and serves to keep the hemisphere B, down in its socket. But it' a strong pressure is exerted on the bolt G, the two hemispheres are firmly wedged down into their sockets, and the seat with the hemisphere B, is retained in the position, into which it may have been brought before the pressure on the bolt is applied.

A longitudinal sliding motion is imparted to the bolt G, by means of two pairs of toggle arms H, which are inserted into a cavity d, in the bottom end of the stand or foot C. The top ends of these toggle arms are retained by notches e, in a metal plate f, that is screwed to the top of the cavity d, and the bottom ends of said ltoggle arms rest in grooves g, on the inner side of the head of the bolt G. The length of the toggle arms H, in relation to the bolt is so adjusted that, if no strain is exerted on the bolt leaving the hemisphere B, with the seat- A, free to be brought in any desired position, the centers of said toggle arms are slightly thrown out of straight lines drawn through their ends as clearly shown in the drawing. By forcing the center of the toggle arms in toward the bolt, their ends are forced apart and a pow* erful pressure in a longitudinal direction is exerted on the bolt Gr.

The toggle arms H, pass through aslot h, in the treadle I, which works in slots z', j in the lower end of the stand O, being retained in its place by a plate 7c, catching into a groove in the end of the treadle. The backs of the toggle arms are slightly curved and the length of the slot z. in the treadle is so adjusted, that the same, when the treadle is raised to the position shown in the drawing, leaves the centers of the toggle arms free to recede from the bolt, so as to exert no pressure on the hemispheres B, and F. But if the treadle is depressed, the ends of the slot h, in sliding down over the backs of the toggle arms, force the centers of the same in toward the bolt, and the pressure thereby exerted on the bolt causes the hemisphcres to be wedged down into their sockets thereby retaining the seat A, in the position, into which it may have been brought before the treadle is depressed.

By these means the operator has both his hands free to bring the patient into the `desired position and to hold him there until by a pressure of the foot on t-he treadle the seat is retained in the desired position.

The construction of this chair is very simple and cheap; both hemispheres B and F, and also the socket D, can be cast and and operating substantially in the manner secured in their placesY Without requiring and for the purpose herein set forth. any fitting and the Whole device is so easily 2. The arrangement of the toggle arms H, put together and adjusted, that it can be and slotted treadle I, in combination with 15 5 done With little loss of time. the bolt G, seat A, and hemispheres B, and Having thus fully described my inven- F, constructed and operating substantially tion what I claim as new and desire to seas and for the purpose specified.

cure by Letters Patent, is V. VAN VLECK.

l. The arrangement of the longitudinally Witnesses: 10 sliding bolt G in ycombination With the seat L. W. BENDR,

A, and hemispheres B, and F, constructed M. M. LIVINGSTON. 

